Now I've seen it all

Here's a photo of an ultra-orthodox Jewish man wrapped in a plastic bag in his airline seat. His reasoning (if one might apply such a word) is unclear but apparently this is done to ensure the Bagged One does not become impure in the eyes of God just in case the plane flies over a Jewish cemetery.

Yeah, I know. What do you mean the cabin is pressurized? That's no good. Gimme a giant see-through plastic bag with a breathing hole poked in it somewhere. That's how you block out the magical nasty.

I guess cabin pressurization isn't hermetically sealed enough. (It doesn't work like a spacecraft, that's airtight; instead they bleed compressed air out of the jet engines' compressors, cool it, mix it with recirculated cabin air (that way everyone can get the cold brought on board by the guy in 27-B), and let it go into the cabin. It eventually leaves the aircraft through an outflow valve, but by constricting this, they can cause the pressure to go up in the cabin.

So in spite of the aircraft being pressurized, air is flowing from the outside through the plane, and back outside constantly. This allows the cooties (or whatever) from the overflown graves to get to you.